U.S. Pat. Nos. 4,255,480; 4,263,081; 4,305,987; and 4,327,141 disclose embodiments which demonstrate abrasion-resistance enhancement of high and low pressure decorative laminates by providing an ultra-thin coating composed of mineral particles and microcrystalline cellulose on the surface of conventional decor paper, followed by impregnating the paper with melamine or polyester resin, and then using the decor paper in a normal laminating process but without the overlay paper. The resultant laminate exhibits abrasion-resistance qualities much better than those of conventionally produced high or low pressure decorative laminates containing an overlay layer.
However, the embodiments illustrated in these patents are directed to the manufacture of abrasion-resistant high and low pressure laminates containing thermosetting resins, and there is no disclosure of the use of microcrystalline cellulose in combination with mineral particles in other environments, particularly for the protection of thermoplastic substrates. Moreover, the ultra-thin coating is applied to one of the elements, e.g. the decor sheet, which becomes part of the final laminate product.
Transfer coating or printing, on the other hand, is well known. For example, there is a considerable body of prior art which shows coating compositions for use in transfer (hot stamp) applications to provide abrasion resistance to thermoplastic resin surfaces. Such heat transfers can include a layer containing inorganic grit particles to enhance abrasion resistance.
As described in patents such as U.S. Pat. Nos. 3,666,516; 4,007,067; 3,770,479; 3,953,635; and 4,084,032, hot stamp tapes are often produced with the following layers, noting FIG. 1:
A. Carrier Sheet or Web--such as films of polyester, cellophane, cellulose acetate, or paper. PA1 B. Primer Coat (optional)--to hold tick coat (see C.) to carrier sheet or web. PA1 C. Tick Coat (optional)--to impart a texture if desired. PA1 D. Release Coating (optional)--to enable release of subsequent coating from the above. PA1 E. Replicating Coat (optional)--to replicate the surface of the carrier sheet or web and surfaces of heretofore coated ticks. PA1 F. Abrasion Coat--to impart abrasion resistance. PA1 G. Color Coat--may be one coat or several to decorate the coating. PA1 H. Adhesion Coat--to enable the transferable portion of the composite to stick to the substrate.
The hot stamp tape produced as described is then applied to a suitable substrate (adhesion coat against the substrate) under heat and pressure, and the carrier sheet or web with primer, tick and release coats, if applicable, are removed leaving the subsequent coats laminated onto the substrate, as shown in FIG. 1.
These hot stamp tapes of the prior art typically do not offer suitable abrasion resistance to be used in environments of high traffic and abrasion. This deficiency has kept hot stamp tapes out of sizable markets.